Mobility management is important work in a wireless mobile communications system. Generally, mobility management may include mobile network handover, cell reselection, and the like of user equipment (UE).
In a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)/LTE-Advanced (LTE-advanced, LTE-A) system, UE may be in an idle state or a connected state. UE in the idle state is not connected to a base station, cannot send data, and performs cell reselection during movement. The UE in the idle state first needs to enter the connected state if the UE needs to send data. The UE in the idle state may enter the connected state after obtaining connection context and a dedicated intra-cell UE identifier by using a radio resource control (RRC) connection establishment process. UE in the connected state is connected to the base station, and can send data and perform handover during movement. The UE in the connected state may enter the idle state by using an RRC connection release process.
A typical procedure of performing handover by the UE in the connected state may include the following operations: A source base station, that is, a base station currently serving the UE, configuring a measurement parameter for the UE; the UE performing measurement and reporting a measurement result to the source base station; the source base station sending a handover request to a target base station, and sending a handover command to the UE after the handover request is acknowledged by the target base station; the UE accessing the target base station, implementing uplink synchronization, and sending a handover complete message; and so on.
In future network evolution, there are increasingly more networking forms such as a heterogeneous network (Hetnet), coordinated multipoint (Coordinated Multiple Points, CoMP) transmission, small cell networking, and dense networking of small cells. These networking forms pose new challenges to UE mobility management. If the current handover procedure is still used, the UE needs to continually perform measurement and reporting. In addition, high handover signaling overheads are caused, and radio resources are wasted.